Find your ring size
Every piece is prepared to your size, so a few minutes of measuring now means a ring that feels made for you the moment it arrives.
Measure a ring you already own
The most accurate way to size at home.
- Choose a ring that fits the intended finger comfortably.
- Lay it flat on a ruler and measure the inside diameter in millimeters, edge to edge, without including the metal.
- Find the closest diameter in the chart below. If you land between two sizes, choose the larger one.
Measure your finger
No ring to measure? A strip of paper or string works well.
- Wrap a thin strip of paper or non-stretch string around the base of your finger.
- Mark where the end overlaps. It should be snug, but still slide over your knuckle.
- Lay it flat and measure from the start to your mark in millimeters. This is your circumference.
- Find the closest circumference in the chart below, and choose the larger size if you're in between.
Measure two or three times to confirm, and measure at the end of the day, when fingers are naturally at their largest.
US ring size chart
| US size | Inside diameter (mm) | Circumference (mm) |
|---|---|---|
| 3 | 14.1 | 44.2 |
| 3.5 | 14.5 | 45.5 |
| 4 | 14.9 | 46.8 |
| 4.5 | 15.3 | 48.0 |
| 5 | 15.7 | 49.3 |
| 5.5 | 16.1 | 50.6 |
| 6 | 16.5 | 51.9 |
| 6.5 | 16.9 | 53.1 |
| 7 | 17.3 | 54.4 |
| 7.5 | 17.7 | 55.7 |
| 8 | 18.1 | 57.0 |
| 8.5 | 18.5 | 58.3 |
| 9 | 18.9 | 59.5 |
| 9.5 | 19.4 | 60.8 |
| 10 | 19.8 | 62.1 |
| 10.5 | 20.2 | 63.4 |
| 11 | 20.6 | 64.6 |
| 11.5 | 21.0 | 65.9 |
| 12 | 21.4 | 67.2 |
| 12.5 | 21.8 | 68.5 |
| 13 | 22.2 | 69.7 |
| 13.5 | 22.6 | 71.0 |
| 14 | 23.0 | 72.3 |
| 14.5 | 23.4 | 73.5 |
| 15 | 23.8 | 74.8 |
Measurements are approximate. Available sizes vary by design, so please check the size options on each piece.
For the best fit
- Wide bands fit tighter. For bands 6 mm or wider, consider going up half a size.
- Mind your knuckle. If your knuckle is larger than the base of your finger, choose a size that slides over it comfortably.
- Temperature matters. Fingers shrink in the cold and swell in the heat. Avoid measuring first thing in the morning or right after exercise.
- Stacking a set? Wedding sets and stacking bands are made in the same size, so measure for the finger they'll be worn on together.
Planning a surprise proposal
Borrow a ring they wear on the same finger, measure its inside diameter, and use the chart above. If you can't borrow one, trace the inside of the ring on paper and send the tracing to our team, and we'll help you choose.
Resizing
Complimentary resizing is available on select pieces within 30 days of delivery, as long as the piece is unworn and in its original condition. Custom-made designs may not be resizable without changing the design. In those cases, our team may offer a remake or another solution, and additional costs may apply.
Still unsure?
Our jewelry specialists are happy to help you find your size before you order. Email support@blackdiamondsnewyork.com or text 646-718-1289 (US only), and add your size or any questions in the order notes at checkout.
